/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
 * Qwt Widget Library
 * Copyright (C) 1997   Josef Wilgen
 * Copyright (C) 2002   Uwe Rathmann
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the Qwt License, Version 1.0
 *****************************************************************************/

#ifndef QWT_DOUBLE_RANGE_H
#define QWT_DOUBLE_RANGE_H

#include "qwt_global.h"

/*!
  \brief A class which controls a value within an interval

  This class is useful as a base class or a member for sliders.
  It represents an interval of type double within which a value can
  be moved. The value can be either an arbitrary point inside
  the interval (see QwtDoubleRange::setValue), or it can be fitted
  into a step raster (see QwtDoubleRange::fitValue and
  QwtDoubleRange::incValue).

  As a special case, a QwtDoubleRange can be periodic, which means that
  a value outside the interval will be mapped to a value inside the
  interval when QwtDoubleRange::setValue(), QwtDoubleRange::fitValue(),
  QwtDoubleRange::incValue() or QwtDoubleRange::incPages() are called.
*/

class QWT_EXPORT QwtDoubleRange
{
public:
    QwtDoubleRange();
    virtual ~QwtDoubleRange();

    void setRange( double vmin, double vmax, 
        double vstep = 0.0, int pagesize = 1 );

    void setValid( bool );
    bool isValid() const;

    virtual void setValue( double );
    double value() const;

    void setPeriodic( bool tf );
    bool periodic() const;

    void setStep( double );
    double step() const;

    double maxValue() const;
    double minValue() const;

    int pageSize() const;

    virtual void incValue( int );
    virtual void incPages( int );
    virtual void fitValue( double );

protected:

    double exactValue() const;
    double exactPrevValue() const;
    double prevValue() const;

    virtual void valueChange();
    virtual void stepChange();
    virtual void rangeChange();

private:
    void setNewValue( double value, bool align = false );

    class PrivateData;
    PrivateData *d_data;
};

#endif
